<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>JavaScript注释和结束符</title>
</head>

<body>
  <script>
    //单行注释
    /* 多行注释 */
    alert('啦啦啦啦')
    //  根据环境决定写不写分号
    alert('哈哈哈哈');


  </script>
</body>

</html>